A torque converter is used to transfer torque from an engine to a transmission in a motor vehicle. The torque converter includes a turbine having an impeller and a turbine, which are engaged by a fluid, so that the rotating impeller drives the turbine. To minimize power losses at high rotational speeds, a clutch is also provided, in order to engage the rotation of the impeller to the output means when needed. The transfer of torque takes place during acceleration of the motor vehicle through the hydrodynamic coupling of the turbine with the impeller, and during normal driving operation through the mechanical coupling of the converter clutch.
During operation, the turbine shell deflects due to forces generated by the fluid moving between the turbine and impeller. If the turbine deflection is high enough while the turbine is subjected to rotational forces, the turbine assembly can contact the blades of the impeller and cause a catastrophic failure due to the differences in rotational speeds between the turbine and impeller. Obviously, this should be avoided.
One way to avoid this problem is to stiffen the turbine shell by using a brazing process. Brazing is a metal joining process where a filler metal is melted and placed between two parts by capillary action. This brazing technique not only adds cost to production, but also unwanted weight to the turbine, which affects the overall performance of the torque converter.
Another way to stiffen the turbine shell is disclosed in United States Patent Application Publication No. 2007/0161483 (Raf) and discloses a method for manufacturing a stiffening element of composite material. The stiffening member comprises a web, at least one flange, and a radius of curvature corresponding to the curvature of the curved shell surface that is supported by the composite stiffening member. Raf fails to disclose or teach, however, a stiffening element that can be integrated into a curved shell surface but rather discloses methods of manufacturing a stiffening member of supporting curved shell surface from either side of the shell.
Thus, there exists a long felt need for a turbine shell with integrated stiffening elements for the turbine of a torque converter.